Last month, Ford announced that it will build 1964 copies of its sweet 2015 Mustang 50th Anniversary Edition coupe. But we have just learned that it will also build one—yes, one—convertible version. And sorry, no matter how much money you give Ford, you can’t buy it.

But you can win it. The one-of-kind droptop will be raffled off at this year’s Woodward Dream Cruise on August 16, with proceeds benefiting the National Multiple Sclerosis Society. As with the 50th Anniversary coupes, the Wimbledon White GT convertible will feature a chrome-accented grille and taillamps, engine-turned aluminum dash trim, two-tone beige and black leather seats with contrast stitching, fancy carpets, and 19-inch Y-spoke wheels. It even gets an owner’s manual in a leather portfolio with a “50 Years” badge on the outside. Ford says this will be the only 2015 Mustang convertible built with a performance pack to include Pirelli P Zero summer tires, Brembo six-piston painted front brake calipers, and a limited-slip differential.

There also will be a badge on the instrument panel engraved with the signature of Ford chairman Bill Ford, and perhaps coolest of all, a “0001 of 0001” serial number.

The raffle tickets cost $20 and can be purchased now through National MS Society, Michigan Chapter or Ford Motor Company while supplies last. Ticket requests can be placed online anytime at this site or you can call 1-800-243-5767 between 8 a.m. and 8 p.m. EDT Monday through Friday. The winner does not need to be present when the ticket is plucked from its receptacle, but we suggest you head to the Dream Cruise anyway, since, if you don’t win, it’s probably your only chance to ever see this thing in person.